Do you know why coffee spills when you walk while holding a cup of it? Do you care?

America's Department of Defense does. According to a recent report from U.S. Senator Jeff Flake (R-AZ), the Defense Advance Research Projects Agency (DARPA) allocated a $172,283 grant to fund a study conducted in 2012 at University of California at Santa Barbara that investigated why coffee spills while you walk.

DARPA is the agency that commissions advanced research on behalf of the Department of Defense. In other words, sloshing coffee was deemed a matter of national security.

The study: Researchers set out to systematically explore the conditions under which coffee spills, "for various walking speeds and initial liquid levels in the cup," the study, which was published by the American Physical Society, noted.

By using an image analysis program that evaluated coffee levels when walking participants were actively paying attention to their coffee cups compared to not paying attention to the coffee, researchers found that "uneven steps or small jerks of the cup" can amplify "the natural oscillations of coffee into a full-blown spill," the APS reported.

The conclusion: Actively focusing on not spilling coffee or putting a lid on your coffee while walking is your best bet for avoiding spills. Spread the good word, everyone.

And get this — researchers even earned an award for the study. Mechanical engineering professor Rouslan Krechetnikov was bestowed the 2012 Ig Nobel Prize, which honors research that "makes people laugh and then think," the College of Engineering at USC Santa Barbara reported.

A whopping $170,000 to help people laugh and think? Giggles are priceless, and for everything else there's the Department of Defense's deep pockets.